In recent years, cloud computing that uses a network and virtual machines (VM) has been spread. Plural servers are installed in a data center used in the cloud computing in some cases, and the virtual machines operate in the servers. Furthermore, plural virtual machines may also operate in a single server. In a case where the virtual machines are arranged or moved in the data center, for a purpose of facilitating a management or the like, virtual machines used in a same tenant are preferably arranged in a same physical server in some cases. Also, to effectively utilize the physical servers, as many of virtual machines as possible may be arranged in the single physical server. The virtual machine transmits and receives data used for executing an application and an execution result of the application with another virtual machine, the server, or the like. For this reason, communications are established between plural virtual machines in a single data center in some times. Furthermore, a virtual machine operating on a server installed in a data center A may also communication with a virtual machine operating on a server installed in a data center B that is different from the data center A.
As a related art technology, a method of allowing a virtual machine to move between physical servers beyond a network segment is proposed. The method is proposed of efficiently reducing power consumption by preferentially arranging the virtual machines in the physical server where facilities such as air conditioning and illumination are common by using this method. Furthermore, a method is also proposed of deciding, when the number of communications accompanied by at least a certain communication amount between two virtual machines executed by different physical machines exceeds a threshold, an arrangement so that these two virtual machines are executed by a same physical machine. Japanese Laid-open Patent Publication No. 2010-26699 and Japanese Laid-open Patent Publication No. 2010-140134 discuss the related art technologies.